A Research Of Secure Orthogonal Frequency Division Multiplexing Passive Optical Network Communication Technology Based On Chaos

With the rapid development of the communication networks,information security has emerged as one of the most important problems concerning the national economy and people's livelihood.On the other hand,with the arrival of the Internet era,the increasing demand for bandwidth has also challenged the traditional access network.Optical OFDM-PON technology for its high bandwidth,large range of services,flexible bandwidth allocation,large business access range,and low equipment operation and management cost,is considered to be one of the most important solutions for the future access network development.Chaos-based encryption OFDM-PON technology combining both advantages of OFDM access technology and the complex characteristics of chaos,can greatly enhance the security of data transmission from the physical layer perspective,and is considered to be one of the most promising candidates of the next generation access networks.Based on the basic principles of chaos,this paper introduces the basic characteristics of chaos and its advantages for encryption firstly.At the same time,by analyzing data conversion process of OFDM communication technology,we get the suitable position to perform data encryption.Then two chaos key distribution methods which can be used in secure OFDM-PON communication system are studied:dynamic synchronization chaotic key distribution method and real-time updates chaotic key distribution method.The feasibility and security of the key distribution methods are analyzed theoretically.Three kinds of chaos-based OFDM-PON structures have been studied in this paper:CO-OFDM-PON based on two-dimension chaos disturbance,DDO-OFDM-PON based on dynamic mapping and three-dimension encryption and DDO-OFDM-PON based on DFT and subcarrier disturbance.Firstly,the theoretical analysis and formula derivation are performed to clarify the feasibility.The key spaces for these three encryption schemes are provided by analyzing the sensitivity to initial values,correlation and randomness of the output sequences.And then through the VPI and MATLAB co-simulation software,we build three simulation communication systems under the different encryption processing methods and give simulation results of the communication performance and the ability to resist statistical analysis.Finally we carry out the transmission experiment based on 25km optical fiber channel for two OFDM-PON secure communication structures based on IM/DD transmission and reception.The experiment results show that the key space for anyone of these three encryption schemes based on chaos is more than 10³⁰,which means all schemes can effectively combat the exhaustive attack and enhance the security of OFDM-PON network data transmission.The encryption scheme based on dynamic chaos mapping which has minimal encryption complexity is the best one among these three schemes.